Will they have to add a few extra minutes of programming to Shark Week? It looks like scientists have discovered a new species of shark, one that’s tiny and glows in the dark. Only the second example of “pocket shark” on the globe, this species has “pockets” containing glands that produce bioluminescent fluid and make it shine. And if a shark could ever be described as adorable, this one’s it. Why hasn’t Mollisquama mississippiensis been identified before? Here’s a one-of-a-kind shark story:
The cute neon shark
Mark Grace, a biologist with NOAA’s Southeast Fisheries Science Center, was processing specimens that had been collected 3,000 feet deep in the central Gulf of Mexico. This was 2013 and the whole lot had been frozen for about three years. Grace came across an animal he didn’t recognize in the mix. He could tell the funky little sea creature, just 5-1/2 inches long with rows of pointy teeth, was a shark. But he’d never seen anything like it. As it turned out, no other human had, either.
This tiny male shark was only the second specimen of something known as a “pocket shark.” They are small enough to fit in a big pocket, but the name comes from two small pockets they have above their pectoral fins. The other pocket shark was captured three decades earlier. That one, Mollisquama Parini, was an adult female around 16 inches long found in the Nazca Submarine Range off the coast of Chile. Notably, she was also a deep-sea dweller discovered 1,083 feet deep.
World’s only American Pocket Shark
Why did this new shark need to be its own species? High-tech lab equipment helped scientists make the call. They couldn’t really dissect this one-of-a-kind specimen. So instead, biologist John Denton and some colleagues at the American Museum of Natural History created the next best thing: A high-res CT scan that created an accurate 3-D picture of the pocket shark, inside and out. “You can isolate different parts of the anatomy—the skin, the jaw, the vertebrae—and rotate them in three dimensions,” Grace said on the NOAA fisheries website. “It’s absolutely mesmerizing.”
Researchers also used x-rays to determine there. was enough of a difference to dub the Gulf of Mexico specimen “The American Pocket Shark.” According to the study’s abstract, published in July 2019, the new species is different because it has a “putative pit organ” below its jaw. It also has 16 clear groups of photophores, glands that produce bioluminescence, “irregularly distributed along many areas of the body.” It possesses 10 fewer vertebrae than the female pocket shark, too.
Like so much marine science, this discovery of a unique new shark species only leads to more questions. Why either species has those pockets is a mystery, for example, though scientists are theorizing that glow-in-the-dark feature might lure mates or repel predators. NOAA scientists have determined that pocket sharks probably occupy “a similar ecological niche” as Cookie Cutter Sharks. Those charmers get their food by biting just the skin of larger marine animals while they’re still alive. Like his peers, Grace said, “I would love to see a pocket shark alive in its environment.” If that never happens, though, anyone with access to the internet can see the scans. They are hosted online at a database created by Gavin Naylor and his students at the College of Charleston.
Everyone is encouraged to click through the database because there’s plenty of mystery to go around. As Henry Bart, director of the Tulane Biodiversity Research Institute, explained on Tulane University’s website: “The fact that only one pocket shark has ever been reported from the Gulf of Mexico, and that it is a new species, underscores how little we know about the Gulf – especially its deeper waters – and how many additional new species from these waters await discovery.”